From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Adjust the link training code to accommodate per-lane drive settings,
if supported by the platform. Actually enabling this will involve
some changes to each platform's .set_signal_level() implementation,
so for the moment all supported platforms will keep using the current
codepath that just uses the same drive settings for all the lanes.
v2: Fix min() vs. max() fumble
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
.../drm/i915/display/intel_dp_link_training.c | 68 +++++++++++++------
1 file changed, 49 insertions(+), 19 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index d52929855cd0..5452f777afac 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -301,21 +301,33 @@ static u8 intel_dp_phy_preemph_max(struct intel_dp *intel_dp,
return preemph_max;
}
-void
-intel_dp_get_adjust_train(struct intel_dp *intel_dp,
- const struct intel_crtc_state *crtc_state,
- enum drm_dp_phy dp_phy,
- const u8 link_status[DP_LINK_STATUS_SIZE])
+static bool has_per_lane_signal_levels(struct drm_i915_private *i915,
+ enum drm_dp_phy dp_phy)
+{
+ return false;
+}
+
+static u8 intel_dp_get_lane_adjust_train(struct intel_dp *intel_dp,
+ const struct intel_crtc_state *crtc_state,
+ enum drm_dp_phy dp_phy,
+ const u8 link_status[DP_LINK_STATUS_SIZE],
+ int lane)
{
u8 v = 0;
u8 p = 0;
- int lane;
u8 voltage_max;
u8 preemph_max;
- for (lane = 0; lane < crtc_state->lane_count; lane++) {
- v = max(v, drm_dp_get_adjust_request_voltage(link_status, lane));
- p = max(p, drm_dp_get_adjust_request_pre_emphasis(link_status, lane));
+ if (has_per_lane_signal_levels(dp_to_i915(intel_dp), dp_phy)) {
+ lane = min(lane, crtc_state->lane_count - 1);
+
+ v = drm_dp_get_adjust_request_voltage(link_status, lane);
+ p = drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
+ } else {
+ for (lane = 0; lane < crtc_state->lane_count; lane++) {
+ v = max(v, drm_dp_get_adjust_request_voltage(link_status, lane));
+ p = max(p, drm_dp_get_adjust_request_pre_emphasis(link_status, lane));
+ }
}
preemph_max = intel_dp_phy_preemph_max(intel_dp, dp_phy);
@@ -328,8 +340,21 @@ intel_dp_get_adjust_train(struct intel_dp *intel_dp,
if (v >= voltage_max)
v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
+ return v | p;
+}
+
+void
+intel_dp_get_adjust_train(struct intel_dp *intel_dp,
+ const struct intel_crtc_state *crtc_state,
+ enum drm_dp_phy dp_phy,
+ const u8 link_status[DP_LINK_STATUS_SIZE])
+{
+ int lane;
+
for (lane = 0; lane < 4; lane++)
- intel_dp->train_set[lane] = v | p;
+ intel_dp->train_set[lane] =
+ intel_dp_get_lane_adjust_train(intel_dp, crtc_state,
+ dp_phy, link_status, lane);
}
static int intel_dp_training_pattern_set_reg(struct intel_dp *intel_dp,
@@ -400,17 +425,22 @@ void intel_dp_set_signal_levels(struct intel_dp *intel_dp,
{
struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
- u8 train_set = intel_dp->train_set[0];
char phy_name[10];
+ int lane;
- drm_dbg_kms(&dev_priv->drm, "Using vswing level %d%s, pre-emphasis level %d%s, at %s\n",
- train_set & DP_TRAIN_VOLTAGE_SWING_MASK,
- train_set & DP_TRAIN_MAX_SWING_REACHED ? " (max)" : "",
- (train_set & DP_TRAIN_PRE_EMPHASIS_MASK) >>
- DP_TRAIN_PRE_EMPHASIS_SHIFT,
- train_set & DP_TRAIN_MAX_PRE_EMPHASIS_REACHED ?
- " (max)" : "",
- intel_dp_phy_name(dp_phy, phy_name, sizeof(phy_name)));
+ for (lane = 0; lane < crtc_state->lane_count; lane++) {
+ u8 train_set = intel_dp->train_set[lane];
+
+ drm_dbg_kms(&dev_priv->drm, "[ENCODER:%d:%s] %s lane %d, vswing level %d%s, pre-emphasis level %d%s\n",
+ encoder->base.base.id, encoder->base.name,
+ intel_dp_phy_name(dp_phy, phy_name, sizeof(phy_name)),
+ lane, train_set & DP_TRAIN_VOLTAGE_SWING_MASK,
+ train_set & DP_TRAIN_MAX_SWING_REACHED ? " (max)" : "",
+ (train_set & DP_TRAIN_PRE_EMPHASIS_MASK) >>
+ DP_TRAIN_PRE_EMPHASIS_SHIFT,
+ train_set & DP_TRAIN_MAX_PRE_EMPHASIS_REACHED ?
+ " (max)" : "");
+ }
if (intel_dp_phy_is_downstream_of_source(intel_dp, dp_phy))
encoder->set_signal_levels(encoder, crtc_state);
--
2.32.0
